Film and blends of polyetheramide block copolymer and ethylene vinyl alcohol copolymer

ABSTRACT

Ethylene vinyl alcohol copolymer is blended with polyetheramide block copolymer to form a novel composition of matter. The blended composition can be extruded and/or coextruded to make packaging films. In the most preferred embodiments, the blend is contained as one layer in a film comprising a multiplicity of layers, and at least the blend layer is molecularly oriented. Methods of making the films are also disclosed.

This is a continuation of application Ser. No. 558,820, filed Dec. 6,1983 now abandoned.

BACKGROUND OF THE INVENTION

Ethylene vinyl alcohol copolymer (EVOH) is known to provide an excellentoxygen barrier property when used in making packaging films. And whilefilms containing EVOH have been developed and are being used, thephysical properties inherent to EVOH lend certain difficulties to thefabrication and use of EVOH-containing films. EVOH is stiff andpunctures easily. EVOH is not readily thermoformed. Orientation of EVOHis accomplished only with difficulty, and within a narrow range ofprocess operating parameters.

These problems are recognized and addressed in U.S. patent applicationSer. No. 249,974 Pat. No. 4,347,332 entitled NYLON/EVOH BLENDS, filed onApr. 1, 1981, in the names of Thomas W. Odorzynski and Jack E. Knott,II; and application Ser. No. 290,172 entitled POLYMERIC BLENDS OF EVOHCOPOLYMER AND FILMS MADE FROM THOSE BLENDS, filed on Sept. 20, 1982, inthe name of David L. Newsome. Another related application is Ser. No.290,171, abandoned, entitled ORIENTED EVOH/NYLON BLEND FILM, filed Aug.5, 1981. The above applications teach improvements in technologyrelating to EVOH-containing films. And while the improvements dorepresent advances in technical knowledge, there remain certain problemsassociated with the use of EVOH polymers.

It is also known that EVOH is susceptible to degradation of its oxygenbarrier property in the presence of high humidity, or moisture vaporcontent, at the EVOH layer. In order to ensure that the EVOH has a lowhumidity environment within which to operate, the EVOH is usually usedin combination with other polymeric layers which are positioned so as toprovide a moisture barrier between the EVOH layer and an environmentpotentially having an unacceptably high moisture content. Thus it iscommon to find EVOH used in multiple layer structures which includemoisture barrier materials such as polyethylenes.

It is further known that EVOH loses some of its sensitivity to moisture,and thus has improved functionality as a barrier component of film, whenit is molecularly oriented or otherwise formed without remelting afterthe making of a film containing EVOH. The process of orienting the EVOH,however, has proved to be difficult because of the physical propertiesof EVOH. In general, the EVOH, either alone, or in a multiple layerfilm, has a tendency to split or tear during the orientation process.Although the mechanism is not known for sure, this tendency might beexplained in terms of the high degree of crystallinity of EVOH films.Whatever the mechanism, processing of EVOH subsequent to forming a filmhas proved to be extremely difficult. This difficulty has retarded largescale use of EVOH in the oriented form. While some oriented films may bemade which are functionally acceptable, many of those films exhibit ahigh haze level, which is commercially unacceptable.

One method of improving the processability of EVOH film is taught bycopending application Ser. No. 249,975 filed Apr. 1, 1981. In thatapplication, it is taught that certain plasticizers may be blended intothe EVOH to improve its performance in the orientation process. Whilethese plasticizers do fulfill the plasticizing role, in that theplasticized EVOH film can be subsequently oriented with ease and theexpected reduced moisture sensitivity can be achieved, the plasticizersmigrate toward the surface of the film and change the film surfaceproperties over a period of time. While the surface properties may notbe critical for some uses, in many cases the changes in surfaceproperties caused by the migration are not acceptable, and another meansof modifying the properties of the EVOH layer is desired.

Another method of improving properties of an EVOH film is set forth inU.S. Pat. No. 4,347,332. In that patent, it is proposed to blend nylon,along with a nylon plasticizer, with the EVOH in order to make a clearand desirable film. While a clear and desirable film may be made by thisprocess, it has been found that, after a relatively short processingtime in the extrusion of some of the polymer blends to form film, gelsbegin to appear in the film and get progressively worse until shut-downof the extrusion process is required.

The critical issue addressed by the inventor, then, is that of modifyingthe EVOH to avoid its undesirable physical characteristics; so that theEVOH layer is susceptible to commercial processes of extrusion andorientation, to produce a commercially acceptable clear barrier film.The perplexing problem is that of discovering a compound or family ofcompounds which can be blended with EVOH to form a compatible blend andwhich will also modify the undesirable properties; all this withoutsuffering the problems of migration and surface property changescommonly associated with plasticizers.

It is an object of this invention to provide a novel composition ofmodified EVOH which can be extruded continuously for long periods oftime to produce novel films tougher than similar films having unmodifiedEVOH.

It is another object of the invention that the novel films be easilysusceptible to orientation in the machine direction--uniaxially--and inboth the machine direction and cross-machine direction--biaxially.

It is a further object that the resulting oriented film be clear, thatis, exhibit a low level of haze. The low haze in the oriented form,then, confirms the functional compatibility of the materials, and, inturn, good layer integrity, while satisfying the appearance requirementsessential to its commercial acceptance. The films should exhibit goodoxygen barrier properties as exemplary of EVOH, and improved oxygenbarrier properties at high humidity, as compared to those in theunoriented form, as exemplary of oriented EVOH.

It is yet another object that the physical properties of the filmsurface, and particularly surface friction, be more or less constantwith time.

SUMMARY OF THE INVENTION

In its most general form, the invention is embodied in a composition ofmatter which is a compatible blend of 5 percent to about 40 percent byweight of a polyetheramide block copolymer (PEBA), and about 60 percentto 95 percent by weight ethylene vinyl alcohol copolymer.

In another form, the invention is a polymeric film which has been madefrom the compatible blend of the polyetheramide block copolymer and theethylene vinyl alcohol copolymer. In some preferred embodiments of thefilm, the film includes, on each surface thereof, a layer of nylonpolymer, the result being a film having at least three layers with twolayers of nylon and a layer of the blend material therebetween. Theremay be additional layers juxtaposed on either or both of the nylonlayers, as discussed hereinafter. The multiple layer embodiments mayprovide ease of processing, economy, and abuse resistance.

In the most preferred form of the article of the invention, the film ismolecularly oriented in a multiple layer structure. Orientation ratiosare 3/1 to 4/1 for uniaxial orientation and 2×2 to 4×4 for biaxialorientation. In such a preferred article, the overall film thickness isabout 1.0 mil, more or less, and the thickness of the blend layer ofethylene vinyl alcohol and polyetheramide block copolymer is about 20%to 50% of the overall thickness of the film.

The invention is further exemplified in a method of making a film. Themethod comprises forming a mixture of 5 weight percent to about 40weight percent of a polyetheramide block copolymer and about 60 percentto 95 percent ethylene vinyl alcohol copolymer, extruding the mixturethrough an extruder and die apparatus to form a film, in which themixture is present as a layer of blended materials of the mixture, andcooling the film. To make the most preferred form of the article of theinvention, the method comprises coextruding the film with a layer ofnylon on each surface of the blend to form a three layer film comprisingnylon on each surface thereof and a core layer of the blend. The film isfinally completed in its most preferred form by reheating it andmolecularly orienting it.

The thus produced film may be used directly, or may be combined withother layers in forming a more complex film. It is contemplated that theabove-described blend layer may be incorporated into any one member of alarge family of films. These films may be constructed by sequentialforming and laminating of the various layers. They may preferrably bemade by coextrusion of all the polymer layers together, optionallyfollowed by simultaneous orientation of all the layers. Variations onthese and other means of forming the films will be obvious to thoseskilled in the art.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a chart representation showing the Shore Hardness of PEBApolymers in relation to other polymers and rubbers.

DETAILED DESCRIPTION OF THE INVENTION

EVOH copolymers useful in this invention generally contain at leastabout 55, up to about 80, weight percent vinyl alcohol. Preferred EVOHcopolymers generally contain about 60 to 75 weight percent of the vinylalcohol moiety. The remainder of the molecule consists primarily ofethylene. There is usually present in the EVOH molecule a residualamount of vinyl acetate, since the EVOH is made by an hydrolysisreaction of the ethylene vinyl acetate molecule. Commercially availableEVOH is highly hydrolyzed, usually to greater than 99 percent by weight.Especially desirable EVOH copolymers are Soarnol ET and Soarnol D soldby Nippon Gohsei, Japan, and EVAL EP-E and EP-F, sold by Kuraray, Japan.

The PEBA copolymers useful in this invention contain blocks of polyamideand polyether moieties in the polymer chain. A general formula for thesepolymers is: ##STR1##

The composition ratio PE/PA in the copolymer may vary from 20/80 to80/20. The polyamide component may be any of the conventionalpolyamides, such as nylon 6, nylon 66, nylon 6/66, nylon 11 and nylon12. The polyether component is usually, but not necessarily, selectedfrom polyoxyethylene, polyoxypropylene and polyoxytetramethylene. Themelting point of known PEBA's is about 120° to 195° C., and the ShoreHardness is about 65D to 60A as shown on the chart of FIG. 1. PreferredPEBA's are sold by Ato Chemie under the tradename PEBAX. Typical oftheir polymer resins is PEBAX 5512, which has a melting point of 190° C.and Shore Hardness of 55D. This PEBA is generally desirable because itsgenerally soft "hardness" is conducive to a softening modification ofthe hard and brittle EVOH when blended with the EVOH. Ohter successfullytested PEBA's are PEBAX 3533 and PEBAX 4033, also sold by Ato Chemie.PEBAX 3533 has a melting point of 162° C. and Shore Hardness of 80A.PEBAX 4033 has a melting point of 168° C. and a Shore Hardness of 40D.

The invention in its broadest sense is represented by a blendcomposition of EVOH and PEBA. The blend contains, by weight, about 60percent to 95 percent EVOH and conversely 5 percent to about 40 percentPEBA, wherein the PEBA functions in the role of a modifier for theEVOH-PEBA blend. The preferred range for the common applications is 10to 20 percent PEBA and 80 to 90 percent EVOH. That preference does varydepending on, for example, the specific EVOH and PEBA polymers used, thefabrication processes, the overall final structure, and the contemplatedenvironments encountered by the finished package. The lower limit of therange, of 5% PEBA, represents a point at which the most desirable PEBA'slose substantial efficiency in the desired affect of the plasticizingfunction. Depending on the specific PEBA, and the specific EVOH, beingused, compositions of up to 40 percent PEBA are contemplated. At thehigher concentrations of PEBA, the oxygen barrier properties normallyattributed to EVOH may be partially compromised, which is probablyattributable to the dilution of the EVOH concentration. Above the upperlimit of the range, of 40% PEBA, the beneficial plasticizing effect isbeing traded for an unacceptable amount of reduction in the oxygenbarrier.

Another aspect of the invention is represented by films made from theEVOH-PEBA blends. While single layer unsupported film may be made byconventional extrusion techniques, the film is preferrably formed aspart of a coextrusion. A typical coextrusion is /nylon/blend/, 0.4 to2.0 mils thick, with the blend layer being about 20% to 50% of thethickness of the two-layer composite. Another typical coextrusion is/nylon/blend/nylon/, 0.4-2.0 mils thick, with the blend layer beingabout 20% to 50% of the thickness of the three layer composite.Constructive to the illustration of the above two and three layercoextrusions, the leading and trailing slashes represent contemplatedadditional layers which may be positioned on either side, or on bothsides, of the coextrusion to provide additional desired functionalproperties. Structures having exemplary ones of such additional layersare shown hereinafter.

A particularly advantageous property of the EVOH-PEBA blends of thisinvention, as compared to the previously mentioned EVOH-nylon blends, isthat they may be processed continuously through extruder-die apparatusfor extended periods of time without gel formation or other polymerdegradation. As a secondary testing technique, to compare processabilityof EVOH-PEBA blends against conventional EVOH-nylon blends, two blendswere processed separately in a Brabender mixer. Each combination ofblend materials was heated to melting and was mixed continuously for onehour while the torque required for mixing was continuously recorded. Inboth cases, the mixing torque was initially less than 1 ft. lb. Thetorque increased steadily with the EVOH-nylon blend; while the torque ofthe EVOH-PEBA blend remained relatively constant. The blend compositionsand the final torques after the one hour of mixing were:

    ______________________________________                                        Blend               Final Torque                                              ______________________________________                                        80% EVOH - 20% PEBA 0.62 ft. lbs.                                             80% EVOH - 20% Nylon 6/66                                                                         9.79 ft. lbs.                                             ______________________________________                                    

The above test data confirm that material in an extruder and dieapparatus processing a conventional EVOH-nylon blend may haveprocess-time limitations; but make no such suggestion for processingblends of EVOH-PEBA. As a primary testing technique, the inventor hassubjected the EVOH-PEBA blend to extended conventional extrusionprocessing and has found no time limitations on extrusion processing ofthe blend compositions of the invention. Because the PEBA contains asignificant proportion of polyamide building blocks, as do all nylons,it would be expected that PEBA's would have extrusive properties similarto those of nylon. As seen in the above test, the PEBA in the blendprovides a critical functional capability not necessarily available whennylon alone is blended with EVOH.

As stated earlier, the most efficient use of EVOH as an oxygen barrier,and particularly as regards use in a moist environment, is in theoriented form, either uniaxially oriented or biaxially oriented. Theinvention is best represented by this most efficient form of the use ofEVOH. Recalling first that the normal orientation problems with EVOH arerelated to its stiffness and rigidity, and that these are commonlyattributed to its crystallinity, in those cases where orientation iscontemplated, the processing operations should provide minimalopportunity for crystal formation in the extrusion process. Thus, whenthe film is to be oriented, the film should be cooled quickly uponexiting the extruder die. Exemplary of acceptable processes toaccomplish this are those where the film is cast against a chill roll asin cast extrusion or where the film is passed through a quenching watermedium as in tubular water quenched extrusion.

Once the film is formed, it may then be reheated and oriented eitheruniaxially or biaxially. This can be done in an in-line operation or anout-of-line operation. In the orientation process, it appears that thePEBA functions as a plasticizing agent for the EVOH. It apparentlyaccomplishes this, however, without the attendant migration of the PEBAto the surface of the layer, as is common with conventionalplasticizers; as no change in surface friction, with time, has beendetected.

Acceptable uniaxial orientation ratios are 3/1 to 4/1. For biaxialorientation, acceptable ratios are 2×2 to 4×4. The higher theorientation ratio, either uniaxial or biaxial, the better are theproperties achieved. The preferred ratio, then, is that highest ratiowhich can be achieved efficiently on available hardware; and that ratiowill vary according to the hardware being used. While biaxialorientation has been represented as being the same amount, or uniform,in both axes of orientation, there may be substantial deviation fromthat sameness, with the only requirement being that the amount ofstretch on each axis is 2 to 4 times the original unstretched dimension.Thus 2×4 orientation is acceptable, for example, as is a 4×2 or a 4×3 ora 3×4. Thus any recitation of a range of uniform biaxial stretchingratios is meant to include all non-uniform ratios possible within therange. The resulting film in any of these cases is uniform and clear.

In retrospect, it is seen, that the results obtained from making a filmfrom a blend of EVOH and PEBA yield a basic understanding of theoperation of the blend material as a polymer. The basic concept derivedis that the PEBA functions to lend its softness, flexibility, andtoughness to the otherwise relatively brittle and fragile EVOH, therebymodifying its properties to yield a film having improved extensibilityand toughness. This concept holds true for all PEBA polymers. Some filmswhich cannot otherwise be successfully oriented become orientable withthe inclusion of PEBA. Also, some films which can be oriented withoutthe inclusion of PEBA are easier to orient, and are tougher films, withthe inclusion of PEBA. Thus, in some cases the inclusion of the PEBAmakes orientation possible, and in other cases it makes orientationeasier.

Regarding the selection of the the specific PEBA to be used, the softerPEBA's can provide the necessary extensibility for moderate orientationratios with the minimum use of PEBA. For the greater toughness requiredof films which are subjected to higher levels of orientation, andprimarily as regards biaxial orientation, the harder PEBA's lendsubstantially more toughness than the softer PEBA's and are generallypreferred. Where toughness is a significant requirement as far as thepackage protecting the product, the primary purpose of the PEBA may beto impart toughness, and a PEBA having more toughness, as represented bya harder Shore Hardness, will be selected. Thus the selection of thespecific PEBA to be used is more or less governed by the amount oforientation and the process and use environments contemplated; althoughit is seen following, that the selection of the specific PEBA may alsobe interdependent on other factors.

The primary factors governing the EVOH/PEBA ratio in the blend have todo with the specific EVOH selected and the contemplated end use. Sincethe functionality of the EVOH as an oxygen barrier is usually theprimary purpose of the layer, the selection of the specific EVOH polymeris usually the first step in designing the EVOH-PEBA blends. Given theselection of the specific EVOH, then for any PEBA selected, there is arange of properties available within the range of EVOH/PEBA ratiosdefined as acceptable. Should that range of properties not satisfy therequired parameters, then the selection of at least one of the specificpolymers is changed. Since the EVOH is the primary operative polymer;and since the PEBA is primarily used for the purpose of modifying theEVOH to facilitate its processing; then, in most cases, where a specificpolymer combination does not provide the required parameters within therange of those available, then the preferred polymer for change,substitution, or modification, is the PEBA. However, if selecting analternate PEBA, or modifying the PEBA, cannot be made to yield therequired parameters, then an alternate EVOH is selected. For example,for use in moist environments, such as for packaging meat or cheese,preferred EVOH has a relatively high ethylene content, such as 40% to45%. Within the context of all EVOH polymers, those polymers having thehigher ethylene content tend to be relatively softer and moreextensible; and so typically they will have lower requirements so far asthe amount of improvement in softness and extensibility is concerned.The blends designed for these uses generally will fall toward the higherend of the EVOH/PEBA ratios given, as the required amount ofmodification, to the EVOH, is somewhat less. The specific PEBA selectedwill, of course, have an affect, too.

For use in dry environments, such as packaging dry snacks like potatochips, the preferred EVOH has a relatively low ethylene content, such as29% to 35%. Within the context of all EVOH polymers, the polymers havingthe lower ethylene content tend to be relatively harder and morebrittle, and so, typically, will have higher requirements as far as theamount of improvement required in softness and extensibility. The blendsdesigned for these uses generally will fall toward the lower end of theEVOH/PEBA ratios given, as the required amount of modification, to theEVOH, is somewhat more. A larger EVOH/PEBA ratio may, of course, be usedwhere a softer PEBA may be selected while still providing both therequired softness and the required toughness.

Regarding specific multiple layer film structures, the EVOH/PEBA mixtureis most conveniently fabricated into a film containing the blend bymeans of a coextrusion process. In most cases, the blend layer is aninterior layer in the structure, as compared to the exterior layers,when coextruded. A typical multiple layer structure includesnylon/blend/nylon, which may be a subassembly or a component of thecompleted film structure. As typical of completed film assemblies, theremay be mentioned:

    ______________________________________                                        Typical Structures of Complete Films                                          ______________________________________                                        nylon/blend/nylon/sealant                                                     nylon/blend/nylon/EVA/sealant                                                 nylon/blend/nylon/tie/EVA/sealant                                             nylon/blend/nylon/tie/EVA/tie/sealant                                         OPP/adh/nylon/blend/nylon/tie/EVA/tie/sealant                                 ______________________________________                                         adh = adhesive                                                                EVA = ethylene vinyl acetate                                                  OPP = oriented polyropylene                                                   sealant = heat sealable polymer                                               tie = adhesive polymers                                                  

Typical materials used in the tie layers of the foregoing structures arethe carboxy modified polymers sold by Chemplex as Plexar 1 and DuPont asCXA 3101. Typical materials used in the sealant layer are ionomer, EVA,and low density polyethylene (LDPE); and indeed blends of some of thesematerials are typically used. There are only two functional requirementsof the sealant layer. First, it must have acceptable adhesion to theadjacent layer. Second, it must have heat sealing properties compatiblewith heat sealing, preferrably by driving heat from a heat seal barthrough all the layers between the sealant layer and the oppositesurface of the film.

It is, of course, possible to make certain conventional modifications tothe films, or to the processes of making them, without affecting thecapabilities of the films to perform their intended functions.

The exemplary film assemblies as shown above may be desirably uniaxiallyoriented, such as by stretch orienting in the machine direction to makeoriented films which are highly desirable for use in packaging dry snackfoods. Similarly they may be biaxially oriented for other packaginguses. It is, of course, highly conventional to add layers to the filmafter the orientation operation. These additional layers, such as OPP,provide additional functional properties.

In the design of some films, it will be found desirable to improve theinterlayer adhesion at certain of the layer interfaces. Where theadhesion is needed within a coextruded film, a tie, or adhesive, polymermay be used as a thin layer for enhancing adhesion between the twolayers it contacts, as shown in the above listing of typical structuresof complete films. As taught in U.S. Pat. Nos. 4,233,367 to Ticknor andRein, 4,239,826 to Knott and Wang, and 4,254,169 to Schroeder, a numberof extrudable adhesives suitable for use are available. Typicaladhesives for use in films of this invention are the products sold byChemplex Company under the PLEXAR designation, the resins sold byMitsubishi Chemical under the AP designation, and the resins sold byDuPont Company under the CXA designation.

These adhesives are usually olefinic polymers or copolymers which employcarboxy modifications of the general nature ##STR2## which provide thedesired bonding capabilities. These adhesive resins are commerciallyavailable, and their uses will be obvious to those skilled in the art.

EXAMPLE 1

Pellets of Soarnol ET ethylene vinyl alcohol copolymer were mixed withpellets of PEBAX 5512 copolymer in a weight ratio of 80% EVOH to 20%PEBA. The solid pellets were dry blended at room temperature to achievea uniform mixture. The thus mixed pellets were extruded in a castcoextrusion process with nylon 6 on each side of the blend layer to forma three layer film of nylon/blend/nylon. The thus produced film was 2.85mils thick. The film was uniaxially oriented at a stretch ratio of 3.5to 1. The resulting stretched film was about 1 mil thick overall. Theblend layer was about 0.4 mil thick. The oriented film was clear,indicating good compatibility. Haze was 1%, according to ASTM D1003.Samples of the oriented film were tested for oxygen permeability andhaze. The reported oxygen permeability was 49 cc/m² /24 hr. day at 73°F., 100% R.H. Haze was 1.0%. The oxygen permeability of thecorresponding unoriented film of the same thickness and thickness ratioswas greater than 200 cc/m² /day under the same test conditions. At 0%R.H. and 73° F., the oxygen permeability of the test film was only 2.5cc/m² /day.

EXAMPLE 2

A film was coextruded and oriented as in EXAMPLE 1 except that the blendratio was 90% by weight EVOH and 10% PEBA. The oxygen permeability at73° F., 100% R.H. was 32 cc/m² /24 hrs. day, and the haze was 1.0%. Theoxygen permeability was less than 1 cc/m² /day at 0% R.H. and 73° F.

COMPARATIVE EXAMPLE 1

A control film was made and oriented as in EXAMPLES 1 and 2 except thatno PEBA was used. The core layer of the 3-layer film was 100% EVOH. Theoxygen permeability was 24 cc/m² /day at 73° F., 100% R.H., but the hazemeasurement was 3.9%. The film was a milky white on the roll. While thefilm may be functional as a barrier film, its appearance ascharacterized by the higher haze makes it unacceptable for commercialapplication, and thus unsaleable.

EXAMPLE 3

Pellets of Soarnol ET were dry blended with pellets of PEBAX 5512 in aweight ratio of 80% Soarnol ET to 20% PEBAX, as in EXAMPLE 1. A 4.25 milfilm was coextruded. The resulting film was biaxially oriented at a2.5×2.5 stretch ratio. The resulting film had good clarity and testedoxygen permeability of 30 cc/m² /24 hr. day at 73° F., 100% R.H.

EXAMPLE 4

A 4.25 mil film was made as in EXAMPLE 3 except that the blend ratio was90% Soarnol ET and 10% PEBAX 5512. The film was biaxially oriented at a2.5×2.5 stretch ratio. The resulting film had good clarity and testedoxygen permeability of 27 cc/m² /24 hr. day at 73° F., 100% R.H.

Those skilled in the art will now recognize that minor amounts of nylonmay be blended into the EVOH/PEBA blend, and same is contemplatedwherever the blend is recited herein.

In testing the films of the invention, including single layer films, noevidence was found of any film surface properties changing with time.Thus it is concluded that the PEBA does not lend variable surfaceproperties to the EVOH-PEBA blend layer; and that the PEBA does notinterfere with the functionality of the EVOH.

Having thus described the invention, what is claimed is:
 1. As acomposition of matter, a polymeric blend, comprising:(a) 5 percent toabout 40 percent by weight polyetheramide block copolymer; and (b) about60 percent to 95 percent by weight ethylene vinyl alcohol copolymer,thepolyetheramide block copolymer having the formula: ##STR3## wherein PAis a polyamide and PE is a polyether, n being an integer indicative ofthe degree of polymerization of the block copolymer, the degree ofpolymerization being such that its Shore Hardness is about 65D to 60A.2. A blend as in claim 1 wherein said polyetheramide block copolymer hasa Shore Hardness of about 55D to 80A.
 3. A polymeric film made from acompatible polymeric blend, said blend comprising:(a) 5 percent to about40 percent by weight polyetheramide block copolymer; and (b) about 60percent to 95 percent by weight ethylene vinyl alcohol copolymer,thepolyetheramide block copolymer having the formula: ##STR4## wherein PAis a polyamide and PE is a polyether, n being an integer indicative ofthe degree of polymerization of the block copolymer, the degree ofpolymerization being such that its Shore Hardness is about 65D to 60A.4. A film as in claim 3 wherein said polyetheramide block copolymer hasa Shore Hardness of about 55D to 80A.
 5. A polymeric film as in claim 3and including, on at least one surface thereof, a layer of nylonpolymer.
 6. A molecularly oriented polymeric film made from a compatiblepolymeric blend, said blend comprising:(a) 5 percent by weight to about40 percent by weight polyetheramide block copolymer; and (b) about 60percent to 95 percent by weight ethylene vinyl alcohol copolymer,thepolyetheramide block copolymer having the formula: ##STR5## wherein PAis polyamide and PE is a polyether, n being an integer indicative of thedegree of polymerization of the block copolymer, the degree ofpolymerization being such that its Shore Hardness is about 65D to 60A.7. An oriented film as in claim 6 and including on at least one surfacethereof, a layer of nylon polymer.
 8. An oriented film as in claim 7wherein said film is uniaxially oriented at a ratio of about 3/1 to 4/1.9. An oriented film as in claim 9 wherein said film is biaxiallyoriented at a ratio of about 2×2 to 4×4.
 10. An oriented film as inclaim 6 wherein said polyetheramide block copolymer has a Shore Hardnessof 55D to 80A.
 11. An oriented film as in claim 7 wherein saidpolyetheramide block copolymer has a Shore Hardness of 55D to 80A. 12.An oriented film as in claim 8 wherein said polyetheramide blockcopolymer has a Shore Hardness of 55D to 80A.
 13. An oriented film as inclaim 9 wherein said polyetheramide block copolymer has a Shore Hardnessof 55D to 80A.
 14. An oriented film as in claim 6 wherein saidpolyetheramide block polymer has a Shore Hardness of about 55D.
 15. Anoriented film as in claim 7 wherein said polyetheramide block copolymerhas a Shore Hardness of about 55D.
 16. An oriented film as in claim 8wherein said polyetheramide block copolymer has a Shore Hardness ofabout 55D.
 17. An oriented film as in claim 9 wherein saidpolyetheramide block copolymer has a Shore Hardness of about 55D.
 18. Anoriented film as in claim 7 wherein the overall film thickness is about0.4 to 2.0 mils and the thickness of said blend layer of ethylene vinylalcohol and polyetheramide block copolymer is about 20% to 50% of theoverall thickness of said film.
 19. An oriented film as in claim 8wherein the overall film thickness is about 0.4 to 2.0 mils, and thethickness of said blend layer of ethylene vinyl alcohol andpolyetheramide block copolymer is about 20% to 50% of the overallthickness of said film.
 20. An oriented film as in claim 9 wherein theoverall film thickness is about 0.4 to 2.0 mils, and the thickness ofsaid blend layer of ethylene vinyl alcohol and polyetheramide blockcopolymer is about 20% to 50% of the overall thickness of said film. 21.A molecularly oriented polymeric film, comprising:(a) a first layer of ablend material comprising: (i) 5 percent to about 40 percent by weightpolyetheramide block copolymer and (ii) about 60 percent to 95 percentby weight ethylene vinyl alcohol copolymer, said first layer having twosurfaces; (b) second and third layers comprising nylon on the opposingsurfaces of said first layer; and (c) a fourth layer on the surface ofsaid third layer and comprising a heat sealable polymer or copolymer,having heat sealing properties compatible with heat sealing,thepolyetheramide block copolymer having the formula: ##STR6## wherein PAis a polyamide and PE is a polyether, n being an integer indicative ofthe degree of polymerization of the block copolymer, the degree ofpolymerization being such that its Shore Hardness is about 65D to 60A.22. A molecularly oriented polymeric film as in claim 21 and including afifth layer of ethylene vinyl acetate between said fourth sealant layerand said third layer.
 23. A molecularly oriented polymeric film as inclaim 21 and including fifth and sixth layers between said fourthsealant layer and said third layer, said fifth layer being ethylenevinyl acetate, said sixth layer being an adhesive polymer comprising acarboxy modified olefin polymer or copolymer; said fifth layer beingadjacent said fourth layer, said sixth layer being adjacent said thirdlayer, said fifth and sixth layers having a common interface.
 24. Amolecularly oriented film as in claim 21 wherein said film is uniaxiallyoriented at an orientation ratio of about 3/1 to 4/1.
 25. A molecularlyoriented film as in claim 22 wherein said film is uniaxially oriented atan orientation ratio of about 3/1 to 4/1.
 26. A molecularly orientedfilm as in claim 23 wherein said film is uniaxially oriented at anorientation ratio of about 3/1 to 4/1.
 27. A molecularly oriented filmas in claim 21 wherein said film is biaxially oriented at a ratio of 2×2to 4×4.
 28. A molecularly oriented film as in claim 22 wherein said filmis biaxially oriented at a ratio of 2×2 to 4×4.
 29. A molecularlyoriented film as in claim 23 wherein said film is biaxially oriented ata ratio of 2×2 to 4×4.
 30. A molecularly oriented film as in claim 21wherein the composition of said fourth sealant layer is chosen from thegroup consisting of low density polyethylene, ethylene vinyl acetate,ionomer, and blends of the members of said group.
 31. A molecularlyoriented film as in claim 22 wherein the composition of said fourthsealant layer is chosen from the group consisting of low densitypolyethylene, ethylene vinyl acetate, ionomer, and blends of the membersof said group.
 32. A molecularly oriented film as in claim 23 whereinthe composition of said fourth sealant layer is chosen from the groupconsisting of low density polyethylene, ethylene vinyl acetate, ionomer,and blends of the members of said group.
 33. A method of making a film,comprising:(a) forming a mixture of 5 weight percent to about 40 weightpercent of polyetheramide block copolymer and about 60 percent to 95percent by weight ethylene vinyl alcohol copolymer; (b) extruding saidmixture through an extruder and die apparatus to form a film in whichsaid mixture is present as a layer of blended materials of said mixture;and (c) cooling said film,the polyetheramide block copolymer having theformula: ##STR7## wherein PA is a polyamide and PE is a polyether, nbeing an integer indicative of the degree of polymerization of the blockcopolymer, the degree of polymerization being such that its ShoreHardness is 65D to 60A.
 34. A method as in claim 33 including thesubsequent steps of reheating the film and molecularly orienting it. 35.A method as in claim 33 and including coextruding, on one surface ofsaid film, a layer of nylon to form a multiple layer film.
 36. A methodas in claim 35 and including the subsequent steps of reheating saidmultiple layer film and molecularly orienting it.
 37. A method as inclaim 33 and including coextruding, on both surfaces of said film,layers of nylon to form a multiple layer film.
 38. A method as in claim37 and including the subsequent steps of reheating the multiple layerfilm and molecularly orienting it.
 39. A method as in claim 36 whereinsaid film is uniaxially oriented at a ratio of about 3/1 to 4/1.
 40. Amethod as in claim 36 wherein said film is biaxially oriented at a ratioof about 2×2 to 4×4.
 41. A method as in claim 38 wherein said film isuniaxially oriented at a ratio of about 3/1 to 4/1.
 42. A method as inclaim 38 wherein said film is biaxially oriented at a ratio of about 2×2to 4×4.